最简单的方法
PHP;">
PHP
$str = "０１２３ＡＢＣＤＦＷＳ＼＂，．？＜＞｛｝［］＊＆＾％＃＠！～（）＋－｜：；";
echo "$str";
echo "
"; $str = preg_replace('/\xa3([\xa1-\xfe])/e','chr(ord(\1)-0x80)',$str); echo $str;
"; $str = preg_replace('/\xa3([\xa1-\xfe])/e','chr(ord(\1)-0x80)',$str); echo $str;
这是网上看来的代码，所有的@R_404_315@的第二个字节减去0X80（即128）所得的数字就是半角所得的数字了。而/e模式表达的是：如果设定了此修正符，preg_replace() 在替换字符串中对逆向引用作正常的替换，将其作为 PHP 代码求值，并用其结果来替换所搜索的字符串。
在非UTF-8模式下这个函数是可行的,但是UTF-8下 这个方法就似乎无效,
方法二：
'0','１' => '1','２' => '2','３' => '3','４' => '4','５' => '5','６' => '6','７' => '7','８' => '8','９' => '9','Ａ' => 'A','Ｂ' => 'B','Ｃ' => 'C','Ｄ' => 'D','Ｅ' => 'E','Ｆ' => 'F','Ｇ' => 'G','Ｈ' => 'H','Ｉ' => 'I','Ｊ' => 'J','Ｋ' => 'K','Ｌ' => 'L','Ｍ' => 'M','Ｎ' => 'N','Ｏ' => 'O','Ｐ' => 'P','Ｑ' => 'Q','Ｒ' => 'R','Ｓ' => 'S','Ｔ' => 'T','Ｕ' => 'U','Ｖ' => 'V','Ｗ' => 'W','Ｘ' => 'X','Ｙ' => 'Y','Ｚ' => 'Z','ａ' => 'a','ｂ' => 'b','ｃ' => 'c','ｄ' => 'd','ｅ' => 'e','ｆ' => 'f','ｇ' => 'g','ｈ' => 'h','ｉ' => 'i','ｊ' => 'j','ｋ' => 'k','ｌ' => 'l','ｍ' => 'm','ｎ' => 'n','ｏ' => 'o','ｐ' => 'p','ｑ' => 'q','ｒ' => 'r','ｓ' => 's','ｔ' => 't','ｕ' => 'u','ｖ' => 'v','ｗ' => 'w','ｘ' => 'x','ｙ' => 'y','ｚ' => 'z');
echo preg_replace_callback("/([\xEF][\xBC][\x90-\x99]|[\xEF][\xBD][\x81-\x9A\xA1-\xBA])/",'next_fchar','０');
function next_fchar($matches){
global $queue;
return $queue[$matches[1]];
}
方法三：
PHP;">
/**
* 字符串半角和全角间相互转换
* @param string $str 待转换的字符串
* @param int $type TODBC:转换为半角；TOSBC，转换为全角
* @return string 返回转换后的字符串
*/
function convertStrType($str,$type) {
$dbc = array(
'０','１','２','３','４','５','６','７','８','９','Ａ','Ｂ','Ｃ','Ｄ','Ｅ','Ｆ','Ｇ','Ｈ','Ｉ','Ｊ','Ｋ','Ｌ','Ｍ','Ｎ','Ｏ','Ｐ','Ｑ','Ｒ','Ｓ','Ｔ','Ｕ','Ｖ','Ｗ','Ｘ','Ｙ','Ｚ','ａ','ｂ','ｃ','ｄ','ｅ','ｆ','ｇ','ｈ','ｉ','ｊ','ｋ','ｌ','ｍ','ｎ','ｏ','ｐ','ｑ','ｒ','ｓ','ｔ','ｕ','ｖ','ｗ','ｘ','ｙ','ｚ','－',' ','：','．','，','／','％','＃','！','＠','＆','（','）','＜','＞','＂','＇','？','［','］','｛','｝','＼','｜','＋','＝','＿','＾','￥','￣','｀');
$sbc = array( //<a href="https://www.jb51.cc/tag/banjiao/" target="_blank" class="keywords">半角</a>
'0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z','a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z','-',' ',':','.',','/','%',' #','!','@','&','(',')','<','>','"','\'','?','[',']','{','}','\\','|','+','=','_','^','~','`');
if($type == 'TODBC'){
return str_replace( $sbc,$dbc,$str ); //半角到全角
}elseif($type == 'TOSBC'){
return str_replace( $dbc,$sbc,$str ); //全角到半角
}else{
return $str;
}
}
方法四：
'0','ｚ' => 'z','（' => '(','）' => ')','〔' => '[','〕' => ']','【' => '[','】' => ']','〖' => '[','〗' => ']','“' => '[','”' => ']','‘' => '[',''' => ']','｛' => '{','｝' => '}','《' => '<','》' => '>','％' => '%','＋' => '+','—' => '-','－' => '-','～' => '-','：' => ':','。' => '.','、' => ','，' => '.','、' => '.','；' => ','？' => '?','！' => '!','…' => '-','‖' => '|','”' => '"',''' => '`','‘' => '`','｜' => '|','〃' => '"',' ' => ' ');
return strtr($str,$arr);
}
全角，又称全形、全宽，是电脑字符的一种格式，字面意思是比普通字符（或半角字符）宽的字符。
传统上，英语或拉丁字母语言使用一字节的空间来存储，而汉字、日语等常使用两字节存储，在使用固定宽度文字的地方，为了使字体看起来整齐，英文字母、数字及其他符号，也由原来只占用一个字空间，改为一概占用两个字的空间来显示，并且使用两个字节来存储。
以上所述就是本文的全部内容了，希望大家能够喜欢。
原文链接：https://www.f2er.com/php/21543.html